Insole

ABSTRACT

The invention relates to an insole (100) for shoes, in particular as a disposable product, having a top layer (200) that comprises a two-ply basic material and faces the foot, and a base layer (202) that is connected to said top layer (200) and faces the shoe, and having a foot surface (104) that faces the foot and an opposite Sole surface (102) that laces the shoe, wherein the top layer (200) and the base layer (202) consist of a staple-fibre nonwoven and bicomponent fibres and absorbent cellulose-based fibres and/or hydrophilic synthetic fibres are contained in the top layer and in the base layer, and wherein the insole has a combination comprising at least two different active-substance groups, the active-substance groups being selected from the group of antimicrobial active substance, odour absorbent and odour-masking substance, and both the base layer (202) and the top layer (200) being assigned at least one active-substance group.

The invention relates to an insole for shoes, in particular as a disposable product with an at least two-layer basic material comprising a top layer facing the foot and a base layer that faces the shoe bonded thereto, and with a foot surface facing the foot and an opposite sole surface that faces the shoe.

A wide variety of insoles are known in the prior art. Among other purposes, they serve to improve foot comfort or cushioning in the shoe or to optimize the fit. Special seasonal insoles are also known, e.g. for the purpose of absorbing foot perspiration during the summer or providing insulation against cold surfaces in winter. A general problem in this case is that the foot perspires in the shoe, and bacteria cause odor formation in shoes and in insoles as well. Numerous variants have been proposed in the prior art in order to prevent this odor formation or release, or at least to control the odor.

For example, EP 0272690 A1 describes a three-layer insole that can be equipped with active substances on both the foot surface and the sole surface.

Further multilayer insoles, in which active substances are provided in order to alleviate odor, are described for example in EP 1472945 A2 and EP 0414634 B1.

Based on the known prior art, the object of the invention is to provide in particular a disposable insole that provides favorable liquid transport within the insole in order to provide a sensation of foot dryness while simultaneously providing favorable odor control.

The object is achieved by means of an insole as described above, wherein the top layer and the base layer consist of a staple fiber nonwoven and bicomponent fibers, absorbent cellulose-based fibers and/or hydrophilic synthetic fibers are contained in the top layer and in the base layer, and the insole contains a combination comprising at least two different active substance groups, the active substance groups being selected from the group of antimicrobial active substances, odor-absorbing agents, and odor-masking substances, and wherein both the top layer and base layer are assigned at least one active substance group.

The bicomponent fibers should preferably be provided with a percentage by weight of at least 10 wt %, preferably at least 15 wt %, and preferably at least 20 wt % based on the total weight of the respective layer. More preferably, the bicomponent fibers show a percentage of the total weight of the respective layer of at most 60 wt %, preferably at most 55 wt %, further preferably at most 50 wt %, further preferably at most 45 wt %, and further preferably at most 40 wt %.

Bicomponent fiber as a synthetic fiber is produced from two polymers of different physical or chemical properties. The two polymers or the two components of a bicomponent fiber can be arranged inside the fiber in various ways, such as for example adjacent to each other, or in particular in a sheath core-arrangement.

The bicomponent fibers used for this invention preferably show a low-melting-point component and a higher-melting-point component, preferably in a sheath core-arrangement, wherein in the case of such a sheath core-arrangement, the sheath then comprises the low-melting-point component.

It was found that the use of bicomponent fibers makes it possible to achieve a more “point-shaped” or partial bonding of the two layers, as bonding takes place only via the lower-melting-point component, in particular the sheath component. The bicomponent fibers result in adhesive point-shaped bonding of the fibers within and between the layers; in comparison to this, in the case of true adhesion of the layers by means of adhesive agents or purely synthetic fibers that melt as a whole, a more filmlike intermediate layer is achieved. The use of bicomponent fibers therefore provides a certain channel structure and thus improves the transfer of liquid from the top layer to the base layer, and thus away from the foot into the insole as well.

It was also found that the use of absorbent cellulosic fibers and/or hydrophilic synthetic fibers, chiefly in the top layer, advantageously improves the adjustability of liquid absorption and binding properties. At the same time, this advantageously contributes toward a dry microclimate of the foot of the user or inside the shoe.

It was also found that the assignment of active substance groups further advantageously contributes toward achievement of a hygienic insole.

The at least two active substance groups are assigned to the top layer and the base layer. This is understood to refer to an arrangement both in the layers and on the layers, here in particular on the foot or sole surface. The active substance groups can both be evenly distributed over the surface and/or thickness of the base layer or the top layer, or areas can be provided that contain less or no active substance as compared to areas that contain more or some of the active substance.

An arrangement on one of the layers is also understood to refer to an arrangement in a coating.

Overall, by providing at least two layers of this basic material, thus making it possible to adjust the liquid absorption and binding properties by selecting the fibers in connection with at least two active substance groups, an improved hygienic insole can be provided.

As polymer materials for the bicomponent fibers, polyester (PES), polyolefins, in particular PP, PE, and/or polyamides, or combinations thereof are by all means conceivable.

Particularly preferably, polyester-based fibers are used for the insole bicomponent fibers. The polyester bicomponent fibers comprise a low-melting-point component of copolyester and a higher-melting-point component of polyester. The polyester bicomponent fibers have a core of polyester (PES) and a sheath of copolyester. Particularly preferably, identical bicomponent fibers are used in the top layer and/or in the base layer.

The hydrophilic synthetic fibers provided in addition to the bicomponent fibers in the nonwoven composition of the base layer and/or top layer preferably all have a higher melting temperature than the low-melting-point component of the bicomponent fibers. Because the melting point of the hydrophilic synthetic fibers further provided in the top layer and/or base layer, and if applicable, of optional further fibers, is higher than the melting point of the at least one component of the bicomponent fibers, these hydrophilic synthetic fibers themselves do not melt. In any case, the absorbent cellulosic fibers have no melting point. By means of this fiber configuration, the layers, in particular the top layer facing the foot, can produce a textile feel and a dry microclimate.

By means of exerting pressure on the layer arrangement of the top layer and base layer and heating the layer arrangement so that the surface of the bicomponent fibers melts, fusion bonds can be formed between the fibers of the top layer and the base layer that bond the layers to one another, as well as fusion bonds within the individual layers, thus advantageously contributing toward partial consolidation of the layers, in particular of the top layer, and therefore positively affecting their abrasion resistance. Strong consolidation by means of the large number of point-shaped bonding sites obtained by using bicomponent fibers can reduce or even eliminate detachment of individual fibers from the fiber composite, and this manifests itself in favorable abrasion resistance.

Advantageously, the density of the bicomponent fibers is 1.0 to 6.5 dtex, in particular 1.2 to 4.0 dtex, and preferably 1.5 to 3.0 dtex. It is particularly advantageous to select fine fibers, as fineness of the fibers can allow a large number of point-shaped bonding sites to be obtained, which has a positive effect on the cohesion of the fibers and layers and thus provides improved abrasion resistance.

The selected length of the bicomponent fibers is advantageously 10 to 80 mm, in particular 20 to 70 mm, and preferably 40 to 50 mm. This advantageously allows penetration of the respective layer and production of bonding sites on the fiber surfaces.

As absorbent cellulosic fibers, fluff pulp, cotton, viscose or combinations thereof can be used in particular.

As hydrophilic synthetic fibers, polymer-based fibers composed of polyolefins, in particular PP or PE, or polymer-based fibers composed of polyester, polymer-based polyamides, or combinations thereof are preferably used, wherein the synthetic fibers can be provided with a hydrophilic bright finish.

Moreover, the use of polyester-based fibers, either as bicomponent fibers and/or as hydrophilic synthetic fibers, has also been found to be particularly advantageous because of their structurally elastic behavior. These fibers have a bulking property that is attributable to their resilience.

According to a preferred embodiment, it can be provided that the base layer and the top layer differ in at least one property. The property can be selected from the group of fiber composition, weight per unit area, thickness, density, and water retention capacity. In this manner, the properties of the layers can better be tailored to one another by using layers that complement one another. For example, the top layer can be configured in such a way that it absorbs perspiration from the boot as quickly as possible and transfers it to the base layer.

It is particularly preferred if the top layer comprises 25-35 wt % bicomponent fibers, in particular polyester-based, at least 20 wt % and preferably at least 30 wt % hydrophilic synthetic fibers, in particular polyester fibers, and if applicable/optionally, also up to 50 wt %, in particular up to 40 wt % cellulose-based fibers, in particular viscose.

Furthermore, it can be provided that the base layer comprises 35-60 wt % bicomponent fibers, preferably polyester-based, at least 40 wt % cellulose-based fibers, in particular cotton fibers, and if applicable/optionally, also up to 10 wt % synthetic fibers, in particular polyester fibers.

It is particularly preferable here if the top layer and/or the base layer are subjected to a consolidation process prior to laminate formation. Known consolidation processes such as thermal consolidation methods, calendering, mechanical needling, water jet needling, etc. can be used. Preferably, combinations of the above-mentioned consolidation processes are used. Particularly preferably, water jet needling or mechanical needling is carried out together with subsequent thermal consolidation. In this manner, both the stability of the layer or layers and that of the product as a whole can be improved, which also results in improved tread properties. In addition, for example, by means of mechanical needling, in particular of the top layer, the porosity of the top layer can be improved, and thus its capacity to allow liquid to pass through.

In order to allow perspiration to be drawn off in the most effective manner possible, it can preferably be provided that the insole has an infiltration time of at most 20 sec, in particular at most 15 sec, and most particularly at most 10 sec. Together with coordination of the structure of the top and base layer, this makes it possible to achieve a dry microclimate of the foot in a particularly favorable manner. The infiltration time is determined according to the following method:

The infiltration time describes the capacity of the insole to keep liquid away from the product surface nearest to the body, i.e. from the foot surface of the insole.

The following test equipment is required:

-   -   a stopwatch graduated in sec,     -   a liquid supply device.     -   The structure of this supply device is discussed in further         detail with reference to FIG. 6a and FIG. 6b , wherein FIG. 6a         is a side view and FIG. 6b a top view. The supply device 300 is         composed of steel with a weight of 500-510 g and has a base         plate 302 with an extension L of 100 mm×100 mm and a total         height h1 of 8 mm. In the middle of this base plate 302, an         opening 304 is made from which a cylinder 306 having an outer         diameter D1 of 25 mm, an inner diameter D2 of 20 mm, and a total         height h3 of 41 mm extends. The lower end of the cylinder, which         is oriented toward the base plate, has a sieve-like structure         308. In this structure are arranged 25 holes 310 with a diameter         of 1 mm. The sieve structure or the holes have a height h2 of 2         mm.     -   A piston stroke pipette, e.g. from Eppendorf, with an accuracy         of 0.5-5 ml, adjustable to a pipetting volume of 2 ml, with a         corresponding pipette tip     -   Test solution: demineralized water.

In order to carry out the test procedure, the test pieces must be laid out flat. Optionally, in the case of curved test products, the edges must be cut in such a way that the test samples can be laid flat.

The test pieces must be conditioned for at least 2 h in a standard climate at 23° C.±2° C. and 50%±2% humidity. The samples must not be kinked or folded in the area provided for placement of the opening cylinder, and other changes and impurities are to be avoided.

The entire insole is used as a test piece.

For the test, the insole is spread out flat, with the upper side facing the foot, i.e. the foot surface, facing upward. The above-described liquid supply device is placed on the spread out test pieces in such a way that the opening of the supply cylinder is positioned on the middle of the insole. 2 ml of test is dispensed onto the test pieces through the opening cylinder. For this purpose, the measuring pipette, with the pipette tip at the level of the upper edge of the opening cylinder and inside the opening cylinder in the middle, is pressed down in one movement, and the 2 ml of test liquid is released. The infiltration time ends and is measured as soon as no more test liquid is visible in the opening cylinder.

For the test, 5 measurements are carried out on 5 insoles.

The infiltration time is given as a mean value in sec without decimal places.

The foot feel can preferably be further improved if the top layer and/or the base layer has/have a water retention capacity of at least 1 g/g and at most 15 g/g (g of liquid per g of nonwoven layer). More preferably, the water retention capacity of the top layer and/or base layer is at least 2 g/g, more particularly at least 4 g/g, and further preferably at least 5 g/g, wherein a particularly preferred embodiment has a maximum value of 12 g/g.

Preferably, the water retention capacity of the base layer is greater than the water retention capacity of the top layer.

The water retention capacity of the insole in particular is between 1 g/g and 15 g/g.

The water retention capacity is determined by the following method.

The following test equipment is used for this purpose:

-   -   An envelope-like dihedral wire mesh between which the subsequent         samples are inserted. The wire mesh has external dimensions of         120 mm×120 mm, with a mesh width of 1.5-2 mm and a mass of         approx. 23±2 g.     -   A beaker or vessel having dimensions suitable for accommodating         the wire mesh     -   a precision balance showing values to two decimal places,     -   a stopwatch graduated in sec,     -   a punch cutter measuring 100×100 mm,     -   demineralized water.

In order to prepare the samples, sample test strips measuring 100 mm×100 mm are punched out of the layer to be tested or the product as a whole. If the samples are to be narrower, narrower test strips are punched out and placed next to one another so that an area of 100×100 mm can be measured.

In order to determine the water retention capacity of the individual layers, the layers are to correspondingly separated from the product as a whole.

Before the test, the samples are conditioned for at least 24 h at 23° C.±2° C. and 50%±2% relative humidity. The test pieces are uniformly clamped into the wire mesh between the covering surfaces thereof with a total weight of at least 1 g (precisely weighed to 0.01 g (M1)). In cases where an individual sample weighs less than 1 g, multiple samples are layered together to form a sample stack, which should weigh at least 1 g. The wire mesh, together with the sample, is immersed in demineralized water and left therein for 60 sec.

After this, the wire mesh, together with the sample, is removed from the liquid, and the liquid is allowed to drip off one corner for a period of 120 sec. The samples are then removed from the wire mesh and again precisely weighed to 0.01 g (M2).

The water absorption capacity is calculated according to the equation (M2−M1)/M1 and then indicated in g/g. The value is obtained as the mean value of 3 determinations rounded off to one decimal place.

It is particularly advantageous in this case if the water retention capacity of the base layer in particular is higher than the water retention capacity of the top layer, allowing the foot perspiration to be stored near the sole and thus at a distance from the foot.

It is particularly favorable if the top layer is configured in such a way that it favorably absorbs liquid, in particular perspiration, and transfers it to the base layer in order to quickly transport the liquid away from the foot. Moreover, it can be favorable if the top layer is capable of distributing the liquid in a lateral direction, i.e. in the surface of the top layer, in order to utilize the capacity of the base layer to absorb liquid in the most uniform manner possible and thus optimally.

In order to ensure favorable bonding between the base layer and the top layer, it is preferable if the two layers are bonded to each other substantially over their entire overlapping surfaces. Particularly preferred is partial bonding or bonding at points distributed over the entire overlapping surface. More preferably, bonding can be carried out by means of embossed patterns. Particularly preferably, the base layer and the top layer are bonded to each other by means of a pattern produced by calendering. By introducing embossed patterns into the layers and bonding of the layers thereby, the capillarity can be increased, thus improving liquid transport. The percentage of embossing points on the entire surface of the insole is preferably 5-15%.

According to the invention, the active substance groups are preferably provided on the foot surface and on the sole surface.

In particular, the odor-absorbing agent is advantageously provided on the sole surface. In this manner, one can prevent odor that is emitted downward from the sole and may become fixed in the shoe as well. In particular, odors that are already present in the shoe can be bound. Moreover, it can also be provided that an odor-absorbing agent is provided in the base layer and not only on the sole surface in order to reduce or prevent odor formation in the layer that stores perspiration.

Odor absorption is to be understood in particular as also referring to an adsorption mechanism.

Furthermore and advantageously, it can be provided that the odor-masking substance is provided on the foot surface and/or in the top layer in order to counteract odor occurring directly on the foot.

In order to further combat odor formation, it can be provided that an antimicrobial active substance is provided on the foot surface and/or in the top layer and/or on the sole surface and/or in the base layer. In this manner, and optionally also by providing the antimicrobial active substance in the layers, i.e. in the top layer and/or in the base layer, odor formation due to bacteria can be counteracted, as the growth of bacteria that decompose perspiration is inhibited or completely prevented. When the antimicrobial active substance is used on the sole surface, it combats microorganisms on the sole side, and thus also combats odor development in the shoe. When the antimicrobial active substance is used on the foot surface and/or in the top layer, it can advantageously contribute toward preventing the occurrence of new odors.

In order to ensure that odors are effectively counteracted, it can be provided that at least one of the active substance groups is not mixed into the base layer and/or the top layer, but remains substantially on the sole and/or foot surface. Particularly preferably, at least two active substance groups are provided exclusively on the sole surface and/or foot surface. It is particularly preferred in this case for at least one active substance group to be provided in particle-bound and/or polymer-bound form on the sole and/or foot surface of the basic material. Preferably, at least two of the active substance groups are provided in particle-bound and/or polymer-bound form on the sole and/or foot surface. In this manner, one can ensure that active substances remain at the desired location and exert their effect there.

Alternatively, it can be provided that at least one active substance group, in particular the antimicrobial active substance, is not provided in particle-bound and/or polymer-bound form on the sole and/or foot surface of the basic material and can thus infuse or is infused into the interior of the respective layer, in particular also into the adjacent layer. This can already be provided by the manufacturer, or it can be the case that at the time of use, the perspiration carries the active substance into the top layer and/or the base layer that together form the basic material. In particular, when the base layer is the main layer that binds perspiration, it is advantageous to have the antimicrobial active substance present in the interior of the layer in order to combat and/or prevent bacterial growth.

It is conceivable to provide an active substance group, e.g. an antimicrobial agent, in the top layer and/or on the top layer, i.e. the foot surface, in order to counteract odor formation due to additional fresh perspiration, and to arrange an odor-absorbing active substance in or on the base layer in order to combat old odors. For example, one can use activated carbon that e.g. can be introduced in a coating applied to the sole surface.

Alternatively, odor-masking substances on or in the top layer can be combined with an odor-absorbing active substance on the sole surface or in the base layer in order to mask newly-occurring odors.

In addition, combinations of odor-masking substances in or on the top layer with antimicrobial active substances in or on the base layer are also conceivable in order to counteract odor formation by inhibiting bacterial growth and mask new odor formation.

It is particularly preferable and effective for combatting odor if a combination of three different active substance groups is provided. The combination thus comprises at least one antimicrobial active substance, an odor-absorbing agent, and an odor-masking substance.

In a particularly preferred embodiment, at least two active substance groups are arranged on one of the surfaces, the sole surface or foot surface, and at least one active substance group is arranged on the other surface, the foot surface or sole surface.

The insole can have a coating on the sole surface that imparts to the sole surface increased frictional force compared to the uncoated sole surface. The coating can consist of point-shaped, line-shaped, and/or sheet-shaped coating elements or combinations thereof. In particular, a coating composed of coating lines is preferably provided.

Preferably, at least one of the active substance groups is inserted into the coating and/or bonded thereto. Particularly preferably, the odor-absorbing agent and/or the antimicrobial active substance is inserted into the coating and/or bonded thereto.

The coating on the sole surface can be composed of a plurality of individual patterns formed by coating lines. The individual patterns are preferably more than a solely point-shaped pattern. In the configuration of a pattern as a line, the line preferably does not extend exclusively as a straight line in only one vector direction, but this pattern of lines has at least one curve and/or at least one kink.

The result is that the coating lines do not run solely in one preferred direction.

Individual patterns can show arrangements as pattern groups in which at least two pattern elements are arranged adjacent to one another and in contact, or in particular also pattern groups in which one pattern element at least partially surrounds or encloses another pattern element, such as for example concentric arrangements, or geometric figures of any kind that lie one inside the other and are in contact at one point.

In contrast to a full-surface coating application, it is also possible by means of a non-full-surface coating on the sole surface, such as in particular a line-shaped coating, to maintain further desired properties of the basic material of the insole, such as for example air permeability and/or breathing activity and/or flexural strength of the insole, at a high level, while simultaneously achieving favorable ergonomic adaptation to the foot of a wearer or on the surface contours of the shoe.

Particularly preferably, the sole surface can be covered by the coating with a coverage ratio of at least 6%, in particular at least 8%, in particular at least 10%, more particularly at least 20% and most particularly of at most 50%, even more particularly at most 40%, and most particularly preferably at most 30%.

It is provided in particular that the coating elements cover the sole surface substantially in its entire extension, i.e. not only in special areas such as the heel and/or the area of the ball of the foot. It is therefore preferably provided that the coating extends over the entire sole surface, wherein depending on the pattern provided, individual areas of the sole surface, such as for example the toe/ball area and/or heel area, can have a higher density of coating elements, and other areas, such as for example the area of the arch of the foot, can have a lower density. In particular, in the embodiment in which at least one active substance group is introduced into the coating or bonded thereto, the areas of the shoe that are susceptible to perspiration and thus odor, such as the areas of the toes/ball of the foot in particular, can be taken into account.

In line-shaped coating elements, the line width can be at least 0.2 mm, in particular at least 0.4 mm, in particular at least 0.5 mm, and more particularly at least 0.6 mm. The line width should preferably be at most 2 mm, more particularly at most 1.6 mm, more particularly at most 1.2 mm, and more particularly at most 1.0 mm. The ratio of line length to line width should be at least 5 times, preferably at least 6 times, further preferably at least 8 times, and even more preferably at least 10 times the line width.

The height of the coating elements should be at least 0.1 mm, in particular at least 0.2 mm. The height of the coating elements should be at most 0.8 mm, more particularly at most 0.6 mm, and more particularly at most 0.4 mm. Measurement of the height can be carried out using a microscope having a corresponding magnification, specifically as the difference between a determined upper edge of the basic material and the upper edge of the coating element.

With these preferred heights of the coating elements, unpleasant haptic effects on the foot are advantageously prevented.

The weight per unit area of the coating on the sole surface can be at least 5 g/m², in particular at least 10 g/m², more particularly at least 15 g/m², and more particularly at least 20 g/m². Towards the top, the weight per unit area should preferably be limited to 50 g/m², and more particularly to at most 30 g/m².

The coating is in particular polymer-based, and more particularly based on a polymer from the group comprising polyolefins (in particular PE, PP), acetates, in particular ethylene vinyl acetate (EVA), polyamides (PA), styrene polymers, or combinations thereof.

As materials for the coating, materials with a Shore A hardness of at least 30, in particular at least 40, in particular at least 50, more particularly at least 60 and most particularly of at most 90, more particularly at most 80, and even more particularly at most 70 are preferably used. Measurement of Shore A hardness is carried out according to the standards DIN 53505:2000-08 and ISO 868:2003(E). A Shore A hardness testing device is used.

The sole side with the coating can have a dynamic friction coefficient measured according to ASTM D 1894-01 of at least 0.6, in particular at least 0.8, and more particularly at least 1.0. The maximum values reached should be at most 2.0, more particularly at most 1.5, and more particularly at most 1.2.

According to the invention, the insole comprises at least two different active substance groups.

The odor-absorbing agent can be selected from the group of the carbons, in particular activated carbon, zeolite, starch, diatomaceous earth, or combinations thereof.

It can be provided that the antimicrobial active substance can be selected from the group of the antimicrobial metals, in particular silver, or the polysaccharides, in particular chitosan, or combinations thereof. Antimicrobial metals are advantageous in that the active substance is first released in the form of ions on entry of liquid, thus making it possible to achieve the required dosing over a long period and to at least limit the amount of the odor-producing bacteria. Silver can preferably be used in the form of silver particles. The silver particles can preferably be composed of a matrix, in particular a glass ceramic matrix having silver bound to its surface and/or bound in its interior.

Moreover, it can be provided that the odor-masking substance is a synthetic and/or naturally-based fragrance-producing substance. Essential oils, as well as perfume oils, are conceivable for this purpose. Particularly preferably, the odor-masking substance is an at least partially bound and/or complexed fragrance, such as for example a perfume embedded in cyclodextrin structures and/or in particular a microencapsulated fragrance that in particular comprises a perfume oil. Microencapsulated fragrances are advantageous in that they can allow delayed release of an active substance. For example, it can be provided that the microcapsules are destroyed by pressure or shearing, i.e. by the weight of the person, for example, thus causing the perfume to be released in a controlled manner.

It is advantageously provided that the antimicrobial active substance is provided in a weight per unit area of 0.001-2 g/m², in particular 0.01-2 g/m², more particularly 0.05-1.5 g/m², more particularly 0.1-1.0 g/m², and more particularly 0.1-0.5 g/m².

It is advantageously provided that the insole is equipped with an antimicrobial active substance in an amount based on the entire insole of 0.0001-2 wt %, in particular 0.001-2 wt %, more particularly 0.002-1.5 wt %, and even more particularly 0.002-1.0 wt %.

The odor-absorbing agent can preferably be provided with a weight per unit area of 0.2-30 g/m², in particular 1-20 g/m², and more particularly 2.5-15 g/m².

It is advantageously provided that the insole is equipped with an odor-absorbing agent in an amount based on the entire insole of 0.1-6 wt %, in particular 0.5-5 wt %, and more particularly 1.0-4 wt %.

Finally, it can be provided that the odor-masking substance is provided in a weight per unit area of 0.1-5 g/m², in particular 0.5-3 g/m², and more particularly 1-2 g/m².

It is advantageously provided that the insole is equipped with an odor-masking substance in an amount based on the entire insole of 0.05-1 wt %, in particular 0.1-0.8 wt %, and more particularly 0.2-0.6 wt %.

It is particularly preferred in this case if the combination of the active substance groups of antimicrobial active substances and odor-absorbing agents are introduced in a weight ratio of 1:2 to 1:500 and/or the combination of the active substance groups of antimicrobial active substances and odor-masking substances are introduced in a weight ratio of 1:0.5 to 1:150.

The basic material comprises, in particular also in the case of a multilayer basic material, a base layer with a weight per unit area preferably of at least 180 g/m², further preferably at least 200 g/m², further preferably at least 220 g/m², further preferably at most 300 g/m², further preferably at most 280 g/m², and further preferably at most 250 g/m². The top layer has in particular a weight per unit area of at least 10 g/m², further preferably at least 15 g/m², further preferably at least 20 g/m², further preferably at most 100 g/m², further preferably at most 90 g/m², and further preferably at most 80 g/m². Depending on the intended purpose of use of the insole, such as e.g. as a variant for the summer or the winter, the top layer can preferably have lower maximum limits for the summer of in particular at most 50 g/m² in weight per unit area, while the top layer for the winter can have higher minimum values of in particular at least 50 g/m² weight per unit area.

Preferably, the thickness of the insole, including a coating on the sole surface, is 1-3 mm, and preferably 1-2 mm.

The thickness of an insole (including a coating) is determined using a specific measuring pressure of 0.5 kPa on a scanner area of 25 cm². In particular, the DMT thickness gauge from the firm Schröder may be used. Moreover, the thickness is determined in accordance with DIN EN ISO 9073-2: 1995.

The insole is preferably a disposable product, i.e. a single use product. In principle, however, insoles that can be washed or cleaned are also conceivable.

Further advantages of the invention can be found in the further documents. The features can be essential to the invention either individually or in combination.

The invention is described in the following with reference to a drawing. The figures show the following:

FIG. 1: an insole according to the invention,

FIG. 2: an insole according to FIG. 1 with an additional coating on the sole surface,

FIG. 3a : a schematic section through the basic material of an insole according to the invention,

FIG. 3b : a schematic diagram of a section of a fiber layer with “adhesion” points of bicomponent fibers,

FIG. 4: diagrams a) to b) show enlarged sections of an insole according to the invention,

FIG. 5: diagrams a) to c) show enlarged sections of an insole according to the invention,

FIG. 6: a schematic diagram of the test device for measuring infiltration time.

FIG. 1 shows a top view of the sole surface of an insole according to the invention 100, wherein the sole surface 102 during use of the insole faces the interior of a shoe and the surface opposite the sole surface 102 faces the foot as a foot-side surface 104. The insole 100 is composed of a two-layer basic material, specifically with a top layer 200 facing the foot and a base layer 202 facing the shoe, as shown in FIG. 3a as a schematic section through the insole 100 according to FIG. 1. The top layer 200 and the base layer 202 are composed of a staple fiber nonwoven. The nonwoven material comprises bicomponent fibers in the top layer and the base layer, indicated by the reference number 150, and absorbent cellulose-based fibers and/or hydrophilic synthetic fibers, indicated by the reference number 152.

In both the top layer 200 and the base layer 202, the total weight of the respective layer preferably comprises at least 10 wt % bicomponent fibers, and an amount of 60 wt % is preferably not exceeded. With their low-melting-point component, preferably the sheath component, the bicomponent fibers contribute toward point-shaped bonding 160 of the fibers in the layers and between the layers, as shown schematically in FIG. 3b . The top layer and the base layer advantageously show a water absorption capacity of at least 2 g/g. The insole shows an infiltration time of at most 20 sec. The basic material is consolidated by being pre-calendered, i.e., passed between a heated calendar roller with protruding embossing projections and a counterpressure roller. In this manner, the surface structure 106 that can be seen in FIG. 1, in this case with point-shaped and rib-shaped embossing structures 109, is formed. The engraving depth achieved by means of the calendering, which is 0.7 mm in the present case, can, however, be set as desired by the person having ordinary skill in the art based on his or her technical expertise. In the embossed area, high-density embossed areas 109 are formed in addition to less dense areas 110. The percentage of the entire surface area accounted for by the high-density areas 109 is 5-15%.

The basic material of the insole has a base layer with a preferred basis weight of 200-300 g/m² and a top layer with a preferred basis weight of 20-100 g/m², and depending on the seasonal use of the insole, a higher weight per unit area of the top layer of 50-100 g/m² can be favored for winter insoles and a lower weight per unit area of 20-50 g/m² can be favored for summer insoles.

As shown in FIG. 2, a coating 112 of coating lines 114 is provided on the sole surface 102 of the insole 100 facing away from the sole of the foot and toward the inside of a shoe. This prevents sliding of the insole 100 inside a shoe. The coating lines 114 are polymer-based and preferably composed of EVA (ethylene vinyl acetate). The material preferably has a Shore A hardness of at least 30, preferably 60-80, and preferably at most 90. The coating is applied by means of an engraving process, wherein the insole 100 is passed between a gravure roller and a counter-roller. The width of the coating lines is preferably 0.5-0.7 mm. The height of the coating lines is preferably 0.2-0.3 mm so that application of the coating pattern will not result in any unpleasant haptic effects on the foot.

The coating shown in FIG. 2 has a plurality of individual patterns 120 that are formed by the coating lines 114. In the case shown, each individual pattern 120 is preferably formed by pattern groups 124, wherein the pattern groups are composed of at least three pattern elements 126, here concentrically arranged circles, and no coating mass is applied between the individual circles of each pattern group forming an individual pattern, thus leaving an uncoated area 116 therein. In this manner, by means of the coating lines 114, a total coverage ratio on the sole surface of approx. 20-25% is achieved. This relatively low coverage ratio of the coating has no substantial effect on the further attributed and desired properties of the basic material of the insole, such as for example air permeability and/or breathing activity.

The dynamic friction coefficient of the coated sole surface, measured in accordance with ASTM D 1894-01, is between 0.8 and 1.4.

In FIG. 4 diagrams a) and b) and FIG. 5 diagrams a) to c), a section is shown through an insole according to the invention 100 comprising a basic material with two layers, specifically a top layer 200 and a base layer 202. The base layer 202 faces a shoe and comprises the sole surface 102. The top layer 200 faces a foot and comprises the foot surface 104. It can be seen in the diagrams that a coating 112 is provided on the sole surface that can be configured analogously to the coating shown in FIG. 2.

In the insole 100, active substances for preventing or alleviating odor are assigned to the base layer 202, in particular the sole surface 102, and to the top layer 200, in particular the foot surface 104 respectively. These active substances are selected from the active substance groups of antimicrobial active substances, odor-absorbing agents, and odor-masking substances.

Examples for the arrangement of two active substance groups are shown in FIGS. 4a and 4 b.

In the design of FIG. 4a , an antimicrobial active substance 204, in this case not in a polymer- or particle-bound configuration, is applied to the foot surface 104 and partially also to the top layer 202, and on the sole surface 102, an odor-absorbing agent 206 is bound into the coating 112. In the design of FIG. 4b , an odor-masking substance 208 is provided on the foot surface and an antimicrobial active substance 210 is provided in the coating 112 on the sole side 102 as active substances.

Examples of the arrangement of the three active substance groups are shown in FIGS. 5a -5 b.

In all of the configurations in FIG. 5a ) to c), the active substances are distributed in such a way that the odor-absorbing agent 206 is provided in the coating 112 on the sole surface 102, wherein a highly-porous, fine granular carbon such as activated carbon is preferably used. The odor-absorbing agent is thus in direct contact with the shoe and odors present therein. In this manner, the odors are directly and rapidly absorbed.

In all three configurations of FIG. 5 as well, the odor-masking substance is provided on the foot surface in the form of microencapsulated fragrances that contain perfume oils, said fragrances being indicated by the reference number 208. The fragrances are released in a dosed and controlled manner by pressure and shearing on use of the insole, which causes the capsules to be destroyed.

In FIG. 5a ), a polysaccharide, indicated here in particular by the reference number 204, is used as an antimicrobial active substance, specifically both on the foot surface 104 and in the nonwoven material of the top layer 200, and partially in the nonwoven material of the base layer 202. This active substance serves to control the odor of fresh foot perspiration in that its antimicrobial activity inhibits the growth of bacteria.

A similar design is shown in FIG. 5b ), wherein the antimicrobial active substance here is in the form of silver particles 210 on the foot surface 104. The silver particles are preferably composed of silver bound to a glass-ceramic matrix.

An alternative design is shown in FIG. 5c ), wherein the same silver particles 210 as in FIG. 5b ) and the odor-absorbing agent 206 are present in the coating 112 on the sole surface 102. In this arrangement, the antimicrobial active substance 210 can serve to control bacterial growth on the sole side, and thus also to control odor in the shoe. New perspiration and the formation of new odors are prevented by the fragrances contained in the odor-masking substances 208 and the perspiration-absorbing action of the top layer 200 and base layer 202.

A measurable antimicrobial action can be achieved by selecting an antimicrobial active substance from the active substance groups and using it in the insole. As examples of this, the embodiments of the insole according to the diagram of FIG. 5a as example 1 and the diagram of FIG. 5b as example 2 are described, and the antimicrobial action thereof is measured.

The insole has a basic material composed of a base layer of 200-300 g/m² and a top layer of 50-100 g/m². The base layer has a fiber composition of 35-60 wt % PES bicomponent fibers and further a mixture of hydrophilic synthetic PES fibers and absorbent cellulosic fibers; the top layer comprises 25-35 wt % of PES bicomponent fibers and further hydrophilic synthetic PES fibers. The top layer is laminated onto the base layer by means of pressure, temperature, and embossing.

In example 1, chitosan is applied to the foot surface as an antimicrobial active substance together with a microencapsulated perfume oil as an odor-masking substance. The amount of chitosan used is 0.05-0.06 wt %, and the amount of the encapsulated perfume oil used is 0.5-0.65 wt %, based respectively on the total weight of the insole. As an odor-absorbing agent, activated carbon is applied to the sole side in a line-shaped polymer coating comprising a content of 1-2% based on the total weight of the insole.

In example 2, as a variant of example 1, particle-bound silver with a content of 0.003-0.005 wt % based on the total weight of the insole is applied to the foot surface as an antimicrobial active substance.

The antimicrobial action is measured in accordance with DIN EN ISO 20743A:2013-12. Staphylococcus epidermidis ATCC 14990 is used as a test microbe. The test is conducted based on the absorption method, and the plate count method is used for quantitative measurement. Changes are made such that NaCl 0.9%+0.05% Tween 80 is used as an inoculation medium and NaCl 0.9%+0.20% Tween 80 is used as an elution medium. Microbial growth over 18 h on the sample is calculated compared to the control or reference material according to the following formula:

A=(log₁₀ C _(t)−log₁₀ C ₀)−(log₁₀ T _(t)−log₁₀ T ₀).

where C denotes the control fabric. T denotes the test sample. log₁₀ C_(t) or log₁₀ T_(t)=general logarithm of the arithmetic mean for the bacterial count after incubation for 18 h in control fabric C or test sample T.

log₁₀ C₀ or log₁₀ T₀=logarithm of the arithmetic mean for the bacterial count immediately after inoculation in control fabric C or test sample T.

A simplified calculation is taken as a basis, with the modification of equating microbial growth log₁₀ C₀ and log₁₀ T₀.

For both example 1 and example 2, strong antibacterial activity was detected, i.e. with a microbial reduction≥3 log CFU.

Such an insole provides good tread comfort, combined with a feeling of foot dryness and reduced odor formation. 

1. An insole (100) for shoes, comprising a basic material containing at least two layers, the basic material comprising a top layer (200) facing the foot and a base layer (202) bonded thereto that faces the shoe, and wherein the top layer (200) has a foot surface facing the foot (104) and the base layer (202) has an opposite sole surface (102) that faces the shoe, and wherein the top layer (200) and the base layer (202) comprise a staple fiber nonwoven and bicomponent fibers, and absorbent cellulose-based fibers and/or hydrophilic synthetic fibers which are contained in the top layer and in the base layer, and wherein the insole further comprises a combination of at least two different active substances, the active substances being selected from the group consisting of antimicrobial active substances, odor-absorbing agents, odor-masking substances, and combinations thereof, and both the base layer (202) and top layer (200) each contain at least one of the active substance groups.
 2. The insole (100) of claim 1, wherein, the base layer (202) and the top layer (200) differ in at least one property, selected from the group consisting of fiber composition, weight per unit area, thickness, density, and water retention capacity.
 3. The insole (100) of claim 1, wherein the insole (100) has an infiltration time of at most 20 seconds.
 4. The insole (100) of claim 1, wherein the top layer (200) and/or the base layer (202) has/have a water retention capacity of at least 1 g/g and at most 15 g/g.
 5. The insole (100) of claim 1, wherein the base layer (202) and the top layer (200) are bonded by an embossed pattern (109).
 6. The insole (100) of claim 1, wherein one of the at least two active substances is an odor-absorbing agent (206) which is provided on the sole surface (102).
 7. The insole (100) of claim 1, wherein one of the at leas two active substances is an odor-masking substance (208) which is provided on the foot surface (104).
 8. The insole (100) of claim 1, wherein one of the at least two active substances is an antimicrobial active substance (204, 210) which is provided on the foot surface (104) and/or in the top layer (200), and/or on the sole surface (102), and/or in the base layer (202).
 9. The insole (100) of claim 1, wherein at least one of the at least two active substances is provided such that it does not penetrate the base layer (202) and/or the top layer (200), and wherein the active substance is provided in particle-bound and/or polymer-bound form on the sole (102), and/or on the foot surface (104) of the basic material.
 10. The insole (100) of claim 1, wherein one of the at least two active substances is not provided in particle-bound and/or polymer-bound form on the sole (102), and/or foot surface (104) of the basic material, and is capable of diffusing into the interior of the respective layer.
 11. The insole (100) of claim 1, wherein the at least two active substances is a combination of three different active substances.
 12. The insole (100) of claim 1, wherein one of the at least two different active substances is arranged on one of the surfaces selected from the sole surface (102) and the foot surface (104), and the other of the at least two active substances is arranged on the other at the two surfaces, selected from the foot surface (104) or the sole surface (102).
 13. The insole (100) of claim 1, wherein on the sole surface (102), a coating (112) is provided that imparts increased frictional force to the sole surface (102) compared to the uncoated sole surface (102).
 14. The insole (100) of claim 13, wherein the coating (112) is not full-surface, but is composed of coating elements selected from the group consisting of point-shaped coating elements, line-shaped coating elements, sheet-shaped coating elements and combinations thereof.
 15. The insole (100) of claim 13, wherein at least one of the at least two different active substances in the coating (112) is added to and/or bonded to said coating.
 16. The insole (100) of claim 1, wherein one of the at least two different active substances is an odor-absorbing agent (206) which is selected from the group consisting of activated carbon, zeolite, starch, diatomaceous earth and combinations thereof.
 17. The insole (100) of claim 1, wherein one of the at least two different active substances is an antimicrobial active substance (204, 210) which is selected from the group consisting of antimicrobial metals, polysaccharides, and combinations thereof.
 18. The insole (100) of claim 1, wherein one of the at least two different active substances is an odor-masking substance (208) which comprises a microencapsulated perfume.
 19. The insole (100) of claim 1, wherein the top layer (200) comprises 25-35 wt % bicomponent fibers, at least 20 wt %, hydrophilic synthetic fibers, and optionally, also up to 50 wt % cellulose-based fibers.
 20. The insole (100) of claim 1, wherein the base layer (202) comprises 35-60 wt % bicomponent fibers at least 40 wt % cellulose-based fibers, and optionally, also up to 10 wt % synthetic fibers.
 21. The insole (100) of claim 1, wherein one of the at least two different active substances is an antimicrobial active substance (204, 210) which is provided in a weight per unit area of 0.001-2 g/m².
 22. The insole (100) of claim 1, wherein one re the at least two different active substances is an odor-absorbing agent (206) which is provided in a weight per unit area of 0.2-30 g/m².
 23. The insole (100) of claim 1, wherein one of the at least two different active substances is an odor-masking substance (208) which is provided in a weight per unit area of 0.1-5 g/m².
 24. The insole (100) of claim 1, wherein the at least two different active substances are the active substance groups of antimicrobial active substances (204, 210) and odor-absorbing agents (206) which are introduced in a weight ratio of 1:2 to 1:500, and/or the active substances are antimicrobial active substances (204, 210) and odor-masking substances (208) which are introduced in a weight ratio of 1:0.5 to 1:150.
 25. The insole (100) of claim 17, wherein the antimicrobial metal is silver and/or the polysaccharide is chitosan.
 26. The insole (100) of claim 19, wherein the biocomponent fibers are polyester-based, and/or the hydrophilic synthetic fibers are polyester fibers, and/or the cellulose based fibers are viscose.
 27. The insole (100) of claim 20, wherein the biocomponent fibers are polyester-based, and/or the cellulose-based fibers are cotton, and/or the synthetic fibers are polyester fibers. 